Jiuquan Iron and Steel Group Co.

Jiayuguan, China

Jiuquan Iron and Steel Group Co.

Jiayuguan, China
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Li J.-B.,Jiuquan Iron and Steel Group Ltd. | Li J.-B.,Northwestern Polytechnical University | Li Y.,Jiuquan Iron and Steel Group Ltd. | Zhang Y.-Y.,Jiuquan Iron and Steel Group Ltd. | Yang G.-Y.,Northwestern Polytechnical University
Journal of Iron and Steel Research | Year: 2017

Effect of heat treatment in ferrite and austenite phase field on microstructure and properties for 430 stainless steel hot rolled sheets was investigated. Also its microstructure and properties were compared with that of the hot rolled sheets after annealing in the industrial batch annealing furnace. The results showed that heat treatment in dual phase temperature range for 430 stainless steel hot rolled sheets could split banded structure along the rolling direction and inhibit the formation of aggregate structure. Compared with the conventional batch annealing process, dual phase region heat processing can significantly increase the elongation of 430 stainless steel hot rolled sheets and lower the yield strength and hardness. It is proved that dual phase region heat processing is also beneficial to improving the forming performance and wrinkle resistance of final cold rolled sheets.


Feng R.,Jiuquan Iron and Steel Group Co. | Chen Y.,Jiuquan Iron and Steel Group Co. | Gao J.,Jiuquan Iron and Steel Group Co.
Proceedings of the World Congress on Intelligent Control and Automation (WCICA) | Year: 2015

This article describes the current situation and problems of annealing furnace heating, cooling and the external gas supply process control. Analyzes the reasons for non-normal flame and proposed artificial intelligence-based solutions. Industrial application and verification by the proposed control strategy is reasonable, operating results to achieve the desired purpose. © 2014 IEEE.


Song X.,University of Science and Technology Beijing | Cheng S.,University of Science and Technology Beijing | Cheng Z.,University of Science and Technology Beijing | Cheng Z.,Jiuquan Iron and Steel Group Co.
ISIJ International | Year: 2012

Steady molten steel flow in CSP (Compact Strip Production) thin slab mold has been calculated via numerical simulation with heat transfer and solidification considered, and then the trajectories of inclusions have been calculated based on the flow field simulated. The solidifying shell has great influence on fluid flow and heat transfer in thin slab CSP mold, thus it should not be neglected while investigating the inclusion metallurgical behavior. The influence of solidifying shell on inclusion behavior has been particularly evaluated. Because the complex and irregular geometry of solidification front, grid of solidification front in mold has been used to judge whether inclusion is absorbed. Through the trajectories of inclusions, a statistics method to study the motion and distribution of inclusions by the "collision event" between inclusions and sampling surfaces has been used. The influence of inclusion diameter, density and casting speed on inclusion removal, also inclusion distribution within the solidifying shell in mold have been evaluated using this method. It is concluded that the distribution of inclusions in solidifying shell is not well-proportioned mainly due to fluid flow pattern in mold, diameter of inclusion, density of inclusion and casting speed. The ratio of inclusion floating to free surface decreases with casting speed rising, and the time for inclusions to float to free surface gets shorter. Inclusions with larger diameter are more possible to be frozen in solidifying shell with shallow skin depth. Removal of inclusions with smaller diameter is not sensitive to the above factors. © 2012 ISIJ.


Li Y.,University of Science and Technology Beijing | Zhang P.,University of Science and Technology Beijing | Cheng S.,University of Science and Technology Beijing | Gao J.,Jiuquan Iron and Steel Group Co.
AISTech - Iron and Steel Technology Conference Proceedings | Year: 2015

Based on two large blast furnaces, the floating heights of deadman were calculated by force balance model and flow field of hearth bottom were analyzed. The position of erosion was directly related to the floating state of deadman in hearth. It would also influence the relationship between bottom and hearth temperature. When deadman was sinking at bottom, the temperature tendency of bottom center and hearth sidewall was contrary. And erosion was near the border between hearth and bottom. The variation of hearth and bottom temperature was complex when deadman was floating. The position of erosion would also migrate. AISTech 2015 Proceedings © 2015 by AIST.


Cheng Z.-J.,University of Science and Technology Beijing | Cheng Z.-J.,Jiuquan Iron and Steel Group Co. | Guo J.,University of Science and Technology Beijing | Cheng S.-S.,University of Science and Technology Beijing
Kang T'ieh/Iron and Steel | Year: 2012

The reasonable content of MgO in refining slag calculated by the thermodynamic calculation software FactSage ranges from 4% to 8%, in which 6% is the best. In addition, slag-steel equilibrium at 1873 K between SiO 2-CaO-Al 2O 3-6%MgO quasi-ternary slag and liquid steel were analyzed on the basis of results of industrial sampling combined that calculated by FactSage both in liquid region and solid-liquid coexisting region with CaO saturation. It indicates that the refining slag with high basicity and high w(CaO)/w(Al 2O 3) (C/A) is favorable for control of low oxygen, low sulfur and low silicon. However, slag with too much CaO is disadvantageous of deoxidation and desiliconization that suggests refining slag is not the whiter the better as the supersaturated CaO do not take part in the slag-steel reaction and even worsen its kinetic conditions. Furthermore, the optimized compositions of refining slag in LF for SPCC in Jiuquan Iron and Steel Corporation (JISCO) are: CaO 50%-55%, Al 2O 3 30%-36%, SiO 2 1%-6%, MgO 4%-8% and 6% is best, basicity 9.0-14.0 and w(CaO)/w(Al 2O 3) is 1.5-1.8. Finally, both slag-steel equilibrium experiments in laboratory scale and industrial trials in plant scale verified that optimized slag has a better ability for deoxidation, desulfurization and control of silicon content, and could better control inclusion composition as well as its removal.


Guo J.,University of Science and Technology Beijing | Cheng S.,University of Science and Technology Beijing | Cheng Z.,University of Science and Technology Beijing | Cheng Z.,Jiuquan Iron and Steel Group Co. | Xin L.,University of Science and Technology Beijing
Steel Research International | Year: 2013

Thermodynamics for CaS bearing inclusions precipitation and their deformative behaviors during compact strip production (CSP) rolling process for Al-killed calcium treatment steel were researched using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) combined with the results of industrial trials. In addition, thermodynamic software FactSage was applied to calculate component activities of an inclusion and to analyze properties of sulfide-oxide duplex inclusions. It is possible for CaS bearing inclusion precipitation during secondary refining and continuous casting in two manners: the first is that Ca and S react directly after calcium treatment; the other is as the well modified calcium aluminates react with dissolved sulfur and aluminum in liquid steel. Correspondingly, two types of sulfide-oxide duplex inclusion were observed in casting slab. For the first type duplex inclusion, nearly no chemical reactions occur between outer CaS layer and solid inclusion core, thus the outer CaS rich layer is easily separated even taken off from the inner core during rolling process, and a crack may be generated correspondingly. The later one performs a better deformation during rolling process. The first type of duplex CaS bearing inclusion forms due to CaS precipitating directly surrounding solid inclusion core; the second type is as modified calcium aluminates react with dissolved sulfur and aluminum. During rolling, the outer CaS rich layer of the first type inclusion is easily separated from the inner core while the later one performs a better deformation. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Jing G.,University of Science and Technology Beijing | Shu-Sen C.,University of Science and Technology Beijing | Zi-Jian C.,University of Science and Technology Beijing | Zi-Jian C.,Jiuquan Iron and Steel Group Co.
ISIJ International | Year: 2013

The formation and modification of non-metallic inclusions for Al-killed steel during Compact Strip Production Process (CSP Process) was studied by industrial experiments. The thermodynamics for the formation of Al 2O3, MgO·Al2O3 spinel, various calcium aluminates and CaS bearing inclusion were analyzed with the help of calculation software FactSage. It is found that the oxygen activity in liquid steel during LF (Ladle Furnace) refining is confirmed to be determined by the equilibrium between dissolved Al and Al2O3 in inclusion. There are two manners for Al2O3 inclusion modification during LF refining: the first route is followed by Al 2O3-low modified calcium aluminates-liquid calcium aluminates; and the other is as Al2O3- MgO·Al 2O3 spinel-CaO-MgO-Al2O3 multi-component inclusion. In addition, the liquid calcium aluminates have the tendency to be multi-component inclusion. Two types of CaS bearing inclusion could precipitate in a slab during solidification. The favorable modified inclusions deform very well along with steel matrix during rolling process even if they are associated with CaS bearing layer, while the no or low modified Al2O3 based inclusion would be rolled into pieces and the micro-cracks might be generated around the inclusions. © 2013 ISIJ.


Chen L.-Z.,Jiuquan Iron and Steel Group Co. | Chang C.-M.,Jiuquan Iron and Steel Group Co. | Wang C.-L.,Jiuquan Iron and Steel Group Co.
Journal of Iron and Steel Research | Year: 2014

The corrosive of the aluminum-zinc-silicon solution on strip steel was investigated by means of experim-ment. At the same immersion temperature, different thinckness of strip steel were immersed in aluminum-zinc-sil-icon solution, after a period of time out, then measure the thinckness of strip steel and analyze the thinning regular. The mechanical properties and corrosion degrees were mainly studied and a further discussion on the corrosion mechanism of the solution on the strip steel was gaven. The results show that the relationship of relative parameters of corrosion behaviors between aluminum-zinc-silicon solution and strips are parabola which the tensile strength and yield strength of the strips will be altered obviously over soak time. The corrosion forms from aluminum-zinc-silicon solution are both pitting and uniform corrosion and in both case, pitting does more damage.


Yan Z.,University of Science and Technology Beijing | Cheng S.-S.,University of Science and Technology Beijing | Cheng Z.-J.,Jiuquan Iron and Steel Group Co.
Ironmaking and Steelmaking | Year: 2014

A three-dimensional (3D) finite element heat transfer model was established to predict temperature in the mould of thin slab continuous casters. The effects of copper plate thickness and scale deposition thickness on temperature were analyzed in detail. The results showed that during casting, the maximum temperatures, about 448°C for the wide hot face and 408°C for the narrow hot face, were found locating in about 60 mm below the meniscus. With copper plate thickness reduced by 4 mm, the maximum temperature decreases by about 50°C for the wide face and 40°C for the narrow face. However, decreasing the copper plate thickness has little effect on cold face (the root of water channel) temperature. The copper plate temperature increases when water slot surface is covered with scale deposits.


Guo J.,University of Science and Technology Beijing | Cheng S.-S.,University of Science and Technology Beijing | Cheng Z.-J.,University of Science and Technology Beijing | Cheng Z.-J.,Jiuquan Iron and Steel Group Co.
Journal of Iron and Steel Research International | Year: 2014

Steel and slag samples were taken at the start and the end of LF refining for steel plate cold common (SPCC), in the compact strip production (CSP) process, and at the same time, the temperature and oxygen activity a[O] were measured by using an oxygen sensor. Furthermore, inclusions in steel samples were monitored by scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS). It was confirmed that a[O] in liquid steel was in equilibrium with inclusion rather than with top slag during LF refining. Desulfurization was related to deoxidation since a[O] at slag-steel interface was clarified to be very close to that in liquid steel under the specific condition in LF with intense stirring by argon blowing and refined by highly basic low oxidizing slag for Al-killed steel. Sulfur partition ratio (LS) was very sensitive to a[O]. Since a[O] increased rapidly with temperature rise, it not only offset promotion to desulfurization reaction with temperature rise but decreased LS. For Al-killed steel, the modification of Al2O3 for lowering the activity of Al2O3 in inclusion was believed to be favorable for both deoxidation and desulfurization during LF refining. © 2014 Central Iron and Steel Research Institute.

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